What is the simple interest formula?

Simple interest = Principal × Rate × Time, where rate is expressed as a decimal and time is in years.

How is simple interest different from compound interest?

Simple interest is always calculated on the original principal only, while compound interest is recalculated on the growing balance including previously earned interest.

Finance Calculators

Simple Interest Calculator

Calculate simple interest and total repayment on a loan or deposit.

Principal amount

Annual interest rate (%)

Time (years)

Interest earned

1500.00

Total amount

11500.00

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About this tool

Work out interest earned or owed using the simple interest formula (principal × rate × time), where interest is calculated only on the original principal — unlike compound interest, it never compounds on itself.

How to use this tool

1
Enter the principal
Type the starting loan or deposit amount.
2
Set the rate and time
Enter the annual interest rate and the number of years.
3
Read the result
See the interest earned and the total amount due.

Frequently asked questions

What is the simple interest formula?: Simple interest = Principal × Rate × Time, where rate is expressed as a decimal and time is in years.
How is simple interest different from compound interest?: Simple interest is always calculated on the original principal only, while compound interest is recalculated on the growing balance including previously earned interest.

FinanceCalculators